Radio receiver with automatic volume control switch



Feb. 5, 1935.

G. HAGEN Filed Dec. 50, 1932 1 Patented Feb. 5, 1935 UNITED s'r-Arts RADIO RECEIVER WITH AUTOMATIC VOLUME CONTROL SWITCH Gerhard Hagen, Berlin,

Germany, assignor to I Telefunken 'Gesellschaft fiir Drahtlos'e Telegraphic m. tion of Germany Application December 30,

In Germany January 22,

b. 11., Berlin, Germany, a, corpora i932, Serial No. 649,453

'1 Claims. (o1; 250-20) The invention is concerned with aradio receiver comprising means adapted to insure automatic volume control. I

Radio receivers which are equipped with a de- 5 vice for automatic regulation of the volume or intensity of reproduction by a loud speaker, especially for the compensation of fading phenomena, involve the drawback that they are difficult to tune to the incoming waves. While in the case of an ordinary receiver set detuning in reierence to the incoming waves manifests itself immedi ately by a marked reduction or the incoming volume, this condition is not quite so conspicuous and apparent in the case of receiver apparatus having automatic volume control means. --Indeed, whatever loss or attenuation may be due to imperfect or, improper tuning will be compensated by a corresponding increase in the gain.

-In other words, imperfect tuning to the user iul, or operating, wave will not manifest itself so much in a loss of reproducing volume as in an pairment of the quality of reproduction. The in: crease in gain, occasioned a result of imperfect tuning of the set,. also results in the fact that the ordinary background noise will be amplified much more markedly, whereby the desired reduction of background noise, usually insured by the use of highly selective tuning means, is lost.

According to this invention, proper tuning of such a receiver set, and thus the insurance of perfect quality of reproduction, is promoted by that circuit means are provided whereby AVC (automatic volume control hereinafter) may be transiently or temporarily rendered inoperative. The tuning of such a set is effected in this manner that first, with the automatic volume control device disconnected, the receiving set is tuned to the incoming wave. The incidentally occurring marked fluctuations in the volume constitute a criterion of the proper tuning.

After tuning has been effected, then'the volume control is rendered operative, and in this manner a compensation of fading vwill be insured in the presence of invariable and optimum receiving conditions.

The novel features which I believe to be characteristic of my invention are set forth in particularity in the appended claims, the invention itself, however, as to both its organization and method of operation will best be understood by reference to the following description takenin connection with the drawing in which I have indicated diagrammatically one circuit organization whereby my invention may be carried into effect.

tively associated with the operating In the drawing, Fig. 1 shows a receiver circuit vention,

Fig. 2 shows invention. I

An embodiment of the basic idea of the invention is shown inthe drawing in Fig. 1; A denotes the antenna, E is the input circuit of the receiver. The inputtube l is here shown as of the screen grid type whose control circuit includes a resitance W traversed by the plate cur rent of thedetector tube 2. A switch S is furincluding the ina tuning knob associated with the nished whereby the resistance W may be bridged andshort-circuited. n

One particular form of l construction incorporatingthe basic idea of this invention is shown Fig, 2 and consists in that the switch S is posie element of the tuning-meansa Thus, the tuning knob 2 driving and controlling the tuning-means 4 is madeelastic. For operating the tuning means it must be subjected to pressure with the switch S. being incidentally closed. When in itsposition of rest (inoperation), the control knobv respond-v ing to the elastic force will keep the switch S in openedcondition.

Fig. 2 shows an arrangement of this kind. 1 denotes the condenser spindle on which is fitted the tuning knob 2. Arranged on the spindle is the disk 3 which is pressed towards the left-hand side by the'agency of a spring 5. If, then, when tuning the knob 2 is pressed inwards, the switch S will be rendered operative by the said disk 3 while the pressure lasts. This closes the switch, and the automatic volume control path is shortcircuited during tuning.

While I have indicated and described one system for carrying my invention into efiect, it will be apparent to one skilled in the art that my invention is by no means limited to the particular organization shown and described, but that many modifications may be made without departing from the scope of my invention asset forth in the appended claims.

What is claimed is:

1. In a radio receiver of the type including an automatic volume control arrangement for a tunable radio frequency amplifier and a tuning means for said amplifier, a switch means for rendering said volume control arrangement inoperative, and means mechanically associated with said tuning means for rendering said switch means inoperative upon actuation of said tuning means whereby said automatic volume control arrangement is operative solely upon adjustment of said timing means to a desired carrier frequency setting.

2. In a radio receiver, a high frequency amplifier, a tuning means therefor including an adjustable tuning shaft, an automatic volume control arrangement electrically associated with the input circuit of said amplifier, a switch for selectively short circuiting said automatic volume control arrangement, and means mounted upon said tuning shaft for closing said switch upon adjustment of said tuning shaft.

3. In a radio receiver, a high frequency amplifier, a tuning means therefor including an adjustable tuning shaft, an automatic volume control arrangement electrically associated with the input circuit of said amplifier, a switch for selectively short circuiting said automatic vol-' ume control arrangement, and means mounted upon said tuning shaft for closing said switch upon adjustment of said tuning shaft, and additional means for normally maintaining said last named means out of contact with said switch.

4. In combination in a radio receiver of the type including a signal amplifier, tuning means for the amplifier, a rectifier, a reproducer and automatic volume control means for regulating the sensitivity of said amplifier in a manner such that the amplifier is at maximum sensitivity when received signals are at a minimum amplitude, auxiliary means for selectively rendering the control means inoperative to regulate the amplifier, and said auxiliary means being operatively associated with the tuning means in such a manner that adjustment solely of the tuning means renders the auxiliary means operative to affect the volume control means whereby the latter is ineffective between signal carrier settings of the tuning means.

5. In combination in a radioreceiver of the type including a signal amplifier, tuning means for the amplifier, a rectifier, a reproducer and automatic volume control means for regulating the sensitivity of said amplifier in a manner such that the amplifier is at maximum sensitivity when received signals are at a minimum amplitude, auxiliary switch means for selectively rendering the control means inoperative to regulate the amplifier, and said auxiliary means being operatively associated with the tuning means in such a manner that adjustment solely of the tuning means renders the auxiliary means operative to affect the volume control means whereby the latter is inefiective between signal carrier settings of the tuning means.

6. In combination in a radio receiver of the type including a signal amplifier, tuning means for the amplifier, a rectifier, a reproducer and automatic volume control means for regulating the sensitivity of said amplifier in a manner such that the amplifier is at maximum sensitivity when received signals are at a minimum amplitude, auxiliary means for selectively rendering the control means inoperative to regulate the amplifier, and said auxiliary means beingoperatively and mechanically associated with the tuning means in such' a manner that adjustment solely of the tuning means renders the auxiliary means operative to affect the volume control means whereby the latter is ineffective between signal carrier settings of the tuning means.

7. In combination in a radio receiver of the type including a signal amplifier, tuning means for the amplifier, a rectifier, a reproducer and automatic volume control means for regulating the sensitivity of said amplifier in a manner such that the amplifier is at maximum sensitivity when received signals are at a minimum amplitude, auxiliary switch means for selectively rendering the control means inoperative to regulate the amplifier, and said auxiliary means being operatively and mechanically associated with the tuning means in such a manner that adjustment solely of the tuning means renders the auxiliary means operative to afiect the volume control means whereby the latter is ineffective between signal carrier settings of the tuning means.

GERHARD HAGEN. 

